Title :
A Compact Ultra-Wideband Bandpass Filter Based on Split-Mode Resonator
Author :
Kuo, Tsung-Nan ; Wang, Chi-Hsueh ; Chen, Chun Hsiung
Author_Institution :
Nat. Taiwan Univ., Taipei
Abstract :
A compact ultra-wideband (UWB) bandpass filter is proposed based on the coplanar-waveguide (CPW) split-mode resonator. By suitably introducing a short-circuited stub to implement the shunt inductance between two quarter wavelength CPW stepped-impedance resonators, a strong magnetic coupling may be realized so that a CPW split-mode resonator may be constructed. Moreover, by properly designing the dual-metal-plane structure, one may accomplish a microstrip-to-CPW feeding mechanism to provide strong enough capacitive coupling for bandwidth enhancement and also introduce an extra electric coupling between input and output ports so that two transmission zeros may be created for selectivity improvement. The implemented UWB filter shows a fractional bandwidth of 116% and two transmission zeros at 1.705 and 11.39 GHz. Good agreement between simulated and measured responses is observed.
Keywords :
band-pass filters; coplanar waveguide components; resonator filters; ultra wideband technology; CPW split-mode resonator; UWB filter; bandwidth enhancement; capacitive coupling; coplanar-waveguide split-mode resonator; dual-metal-plane structure; electric coupling; frequency 1.705 GHz; frequency 11.39 GHz; magnetic coupling; microstrip-to-CPW feeding mechanism; short-circuited stub; shunt inductance; stepped-impedance resonators; transmission zeros; ultra wideband bandpass filter; Band pass filters; Bandwidth; Circuits; Coplanar waveguides; Couplings; Filtering theory; Microstrip filters; Microstrip resonators; Resonator filters; Ultra wideband technology; Bandpass filter (BPF); coplanar waveguide (CPW); dual-plane structure; microstrip; split-mode resonator; ultra-wideband (UWB);
Journal_Title :
Microwave and Wireless Components Letters, IEEE
DOI :
10.1109/LMWC.2007.910483
